Dosimetric review of cardiac implantable electronic device patients receiving radiotherapy

Abstract

A formal communication process was established and evaluated for the management of patients with cardiac implantable electronic devices (CIEDs) receiving radiation therapy (RT). Methods to estimate dose to the CIED were evaluated for their appropriateness in the management of these patients. A retrospective, institutional review board (IRB) approved study of 69 patients with CIEDs treated with RT between 2005 and 2011 was performed. The treatment sites, techniques, and the estimated doses to the CIEDs were analyzed and compared to estimates from published peripheral dose (PD) data and three treatment planning systems (TPSs) — UMPlan, Eclipse's AAA and Acuros algorithms. When measurements were indicated, radiation doses to the CIEDs ranged from 0.01–5.06 Gy. Total peripheral dose estimates based on publications differed from TLD measurements by an average of 0.94 Gy (0.05–4.49 Gy) and 0.51 Gy (0–2.74 Gy) for CIEDs within 2.5 cm and between 2.5 and 10 cm of the treatment field edge, respectively. Total peripheral dose estimates based on three TPSs differed from measurements by an average of 0.69 Gy (0.02–3.72 Gy) for CIEDs within 2.5 cm of the field edge. Of the 69 patients evaluated in this study, only two with defibrillators experienced a partial reset of their device during treatment. Based on this study, few CIED‐related events were observed during RT. The only noted correlation with treatment parameters for these two events was beam energy, as both patients were treated with high‐energy photon beams (16 MV). Differences in estimated and measured CIED doses were observed when using published PD data and TPS calculations. As such, we continue to follow conservative guidelines and measure CIED doses when the device is within 10 cm of the field or the estimated dose is greater than 2 Gy for pacemakers or 1 Gy for defibrillators.PACS number: 87.55.N‐

A review of implantable cardioverter defibrillator failures during radiation therapy in three Sydney hospitals

“…If these statistics are applied to the expected treatment rates published by the Radiation Oncology Tripartite Committee, it is possible that in 2008, across Australia up to 13 ICD patients would have experienced a POR as a result of their radiation therapy. The rate of failure in this study, observed at 22%, is lower than that found by Prisciandaro et al . who reported two power on resets occurring in ICDs from five observed treatments between 2005 and 2011, thereby giving a failure rate of 40%.…”

“…John and Kaye 7 reported on a shock coil failure, and one case study detailed the collapse of a patient during the third fraction of a radiation therapy treatment course 8 with an ICD that could not be reset and had to be explanted in emergency. Further large scale observational studies have continued to show POR occurring at energies 10 MV or greater, [11][12][13][14][15][16][17][18] with Zaremba et al 16 noting a fivefold increase in device malfunction when using energies greater than 15 MV. Dose recommendations for ICDs vary between the literature, with recommendations commonly suggesting 1 Gy, 16,17,19 but as high as 10 Gy.…”

Management of radiotherapy patients with implanted cardiac pacemakers and defibrillators: A Report of the AAPM TG‐203†

“…Given that the bulk of experience is based on conventional dose-rates, increased monitoring (pre-and posttreatment) may be necessary when hypofractionation is used, in agreement with the 2017 HRS expert consensus. 22 Especially, if the patient would benefit from a different dose-rate offered by IMRT/VMAT, SBRT, or FFF beams, such an approach is almost certainly appropriate given the low risk from dose-rate effects and the limited data 70 indicating an elevated risk.…”

“…121 In another study that included IMRT, two partial reset events were identified, but concluded to be related to the high photon energy (16 MV) used. 70 In order to obtain a better understanding of this sensitivity, authors who publish case reports of CIED malfunctions in the future should provide more details on the irradiation technique and conditions than have been reported in the past. Furthermore, an in vitro study of sensitivity of CIEDs to scatter dose from any sort of dynamically modulated delivery is of future interest.…”

Experimental assessment of out‐of‐field dose components in high energy electron beams used in external beam radiotherapy

“…In addition, an accurate evaluation of out-of-field dose from photon beam or electron beam may be important for RT patients having cardiac implantable devices. (2) To date, most studies on out-of-field dose estimation focus on photon beams. (3,4) Nevertheless, electron beams are still an important component of RT, for treating superficial tumors (at depths < 5 cm).…”